Conventionally, among electrical connectors, waterproof connectors which prevent water from entering the connecting portion with a mating connector are known. The air bag systems of automobiles send an electrical signal to the ignition device to cause an explosion, and the gas generated from the explosion fills the air bag. The wiring which sends the electrical signal in the air bag system is connected to the mating connector on the ignition device through an electrical connector. Recently, air bag devices have come to be installed not only in the steering portion in the interior of automobiles, but also, inside the doors as a curtain air bag or a side air bag. Since condensation or the like is more likely to be formed inside the doors compared with the interior, the connectors used inside the doors needs to be waterproof For this reason, waterproof electrical connectors equipped with waterproof rings made of elastic materials have been proposed (see, for example, Japanese Patent Application Laid-open Publications Nos. 2004-193079 and 2005-050685).
Prior Art FIG. 8 and Prior Art FIG. 9 are cross-sectional views showing the conventional waterproof electrical connectors.
Prior Art FIG. 8 shows a waterproof connector 80 which is connected to a mating connector 85 on the ignition device side, while the inner structure of the waterproof connector 80 is omitted. A waterproof ring 82 made of an elastic material is attached to the outer periphery portion of a housing 81 of the waterproof connector 80. When the waterproof connector 80 is fitted into the mating connector 85, contacts (not shown) provided to both of the waterproof connector 80 and the mating connector 85 come into contact with each other. Furthermore, the waterproof ring 82 closely contacts the aperture portion of a contact-receiving concave portion of the mating connector 85, and thus seals the gap between the contact-receiving concave portion and the housing 81.
A waterproof connector 90 shown in Prior Art FIG. 9 is a different type of waterproof connector from that shown in Prior Art FIG. 8. The outer diameter of a waterproof ring 92 is formed to be larger than the diameter of the aperture of the contact-receiving concave portion of a mating connector 95. Accordingly, when a housing 91 is inserted into and received by the contact-receiving concave portion of the mating connector 95, the housing 91 is locked with the mating connector 95, while the waterproof ring 92 is held between the housing 91 and the rims of the contact-receiving concave portion of the mating connector 95 in the direction of insertion. The waterproof connectors 80 and 90 shown, respectively, in Prior Art FIG. 8 and Prior Art FIG. 9, make the connecting portions of the contacts waterproof.
However, some connectors have a notch formed on the aperture portion of the contact-receiving concave portion thereof in prevent relative rotational movement between the waterproof connector and the mating connector. When the conventional waterproof connecter 80 or 90 is fitted into mating connectors having a notch for preventing rotational movement, a gap is formed at the position where the notch is formed, compromising the waterproof seal. Moreover, the waterproof connector 90 shown in Prior Art FIG. 9 is locked with the mating connector 95 while the waterproof ring 92 is tightly held by the aperture portion of the mating connector 95. As a result, the waterproof ring 92 continues to be pressed strongly and is worn out, compromising the waterproof seal.
Further, if a sealing member is attached to a housing after the sealing member is formed as a separate waterproof ring, a groove (or the like) for attaching the waterproof ring and a securing member for securing the waterproof ring are required to be formed in the housing. As squib connectors have been miniaturized to fit to the mating connectors that have also been miniaturized, the thickness of the fitting section of the housing has become thin. As a result, it is difficult to attach the waterproof ring and the securing member for the waterproof ring without altering the contour structure of the squib connectors.